Asus P8C WS - Manual (Page 30)

2-12 Chapter 2: Hardware information
Chapter 2
2.2.6 Onboard LEDs
1. POST State LEDs
The POST State LEDs indicate the status of these key components during POST
(Power-on-Self Test): CPU, memory modules, VGA card, and hard disk drive. If an
error is found, the critical component’s LED stays lit up until the problem is solved.
2. GPU Boost LED
The GPU Boost LED lights up when the GPU Boost switch is turned to Enable.